proguard.classfile.attribute.LineNumberTableAttribute Maven / Gradle / Ivy

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ProGuardCORE is a free library to read, analyze, modify, and write Java class files.
There is a newer version: 9.1.6
/*
 * ProGuardCORE -- library to process Java bytecode.
 *
 * Copyright (c) 2002-2020 Guardsquare NV
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package proguard.classfile.attribute;

import proguard.classfile.*;
import proguard.classfile.attribute.visitor.*;

/**
 * This {@link Attribute} represents a line number table attribute.
 *
 * @author Eric Lafortune
 */
public class LineNumberTableAttribute extends Attribute {
  public int u2lineNumberTableLength;
  public LineNumberInfo[] lineNumberTable;

  /** Creates an uninitialized LineNumberTableAttribute. */
  public LineNumberTableAttribute() {}

  /** Creates an initialized LineNumberTableAttribute. */
  public LineNumberTableAttribute(
      int u2attributeNameIndex, int u2lineNumberTableLength, LineNumberInfo[] lineNumberTable) {
    super(u2attributeNameIndex);

    this.u2lineNumberTableLength = u2lineNumberTableLength;
    this.lineNumberTable = lineNumberTable;
  }

  /** Returns the line number corresponding to the given byte code program counter. */
  public int getLineNumber(int pc) {
    LineNumberInfo info = getLineNumberInfo(pc);

    return info == null ? 0 : info.u2lineNumber;
  }

  /** Returns the source corresponding to the given byte code program counter. */
  public String getSource(int pc) {
    LineNumberInfo info = getLineNumberInfo(pc);

    return info == null ? null : info.getSource();
  }

  /** Returns the line number info corresponding to the given byte code program counter. */
  public LineNumberInfo getLineNumberInfo(int pc) {
    for (int index = u2lineNumberTableLength - 1; index >= 0; index--) {
      LineNumberInfo info = lineNumberTable[index];
      if (pc >= info.u2startPC) {
        return info;
      }
    }

    return u2lineNumberTableLength > 0 ? lineNumberTable[0] : null;
  }

  /**
   * Returns the lowest line number with the default null source, or 0 if there aren't any such line
   * numbers.
   */
  public int getLowestLineNumber() {
    int lowestLineNumber = Integer.MAX_VALUE;

    for (int index = 0; index < u2lineNumberTableLength; index++) {
      LineNumberInfo info = lineNumberTable[index];
      if (info.getSource() == null) {
        int lineNumber = info.u2lineNumber;
        if (lineNumber < lowestLineNumber) {
          lowestLineNumber = lineNumber;
        }
      }
    }

    return lowestLineNumber == Integer.MAX_VALUE ? 0 : lowestLineNumber;
  }

  /**
   * Returns the highest line number with the default null source, or 0 if there aren't any such
   * line numbers.
   */
  public int getHighestLineNumber() {
    int highestLineNumber = 0;

    for (int index = 0; index < u2lineNumberTableLength; index++) {
      LineNumberInfo info = lineNumberTable[index];
      if (info.getSource() == null) {
        int lineNumber = info.u2lineNumber;
        if (lineNumber > highestLineNumber) {
          highestLineNumber = lineNumber;
        }
      }
    }

    return highestLineNumber;
  }

  // Implementations for Attribute.

  public void accept(
      Clazz clazz, Method method, CodeAttribute codeAttribute, AttributeVisitor attributeVisitor) {
    attributeVisitor.visitLineNumberTableAttribute(clazz, method, codeAttribute, this);
  }

  /** Applies the given visitor to all line numbers. */
  public void lineNumbersAccept(
      Clazz clazz,
      Method method,
      CodeAttribute codeAttribute,
      LineNumberInfoVisitor lineNumberInfoVisitor) {
    for (int index = 0; index < u2lineNumberTableLength; index++) {
      // We don't need double dispatching here, since there is only one
      // type of LineNumberInfo.
      lineNumberInfoVisitor.visitLineNumberInfo(
          clazz, method, codeAttribute, lineNumberTable[index]);
    }
  }
}